"Doing more exercise with less intensity,"
Arthur Jones believes, "has all but
destroyed the actual great value
of weight training. Something
must be done . . . and quickly."
The New Bodybuilding for
Old-School Results supplies
MUCH of that "something."

This is one of 93 photos of Andy McCutcheon that are used in The New High-Intensity Training to illustrate the recommended exercises.

The X-Force line-up includes eight single-joint and six multiple-joint machines. Above is a prototype of the X-Force Pec Arm Cross. The framework on the left contains an electric motor at the bottom that powers a tilting weight stack, which is the key to providing more work in less time.

(This is a revised version of a brochure that I researched and wrote for the IHRSA Convention and Trade Show in San Francisco on March 16-19, 2009.)

Beginning in the early 1900s, there were a number of bodybuilding campaigns throughout the United States that claimed to make the weak strong.

These promotions were started by Bernarr Macfadden, a health enthusiast and magazine publisher — and were continued by Charles Atlas, winner in 1922 of the Macfadden-sponsored contest, "America's Most Perfectly Developed Man."

The overriding message of the advertisements, as well as their follow-up mail-order courses, was... Weakness is a crime. The underlying theme was... A lack of muscular size and strength is a disservice to self, country, and humanity.

Macfadden's and Atlas's courses motivated millions of males — before, during, and after World War I and World War II — to get bigger and stronger.

A 1902 edition of Macfadden's popular bodybuilding magazine,Physical Culture. A young, muscular Macfadden was featured on this cover. The periodical's circulation was highest during the mid 1920s.

FORGING WEAKNESS INTO STRENGTH

For the first half of the 20th Century, the basic method of gaining strength involved lifting barbells and dumbbells — mixed with body-weight exercises such as push-ups, sit-ups, and chin-ups. These routines focused on the raising or positive phase, with little regard to the lowering or negative.

In 1972, Arthur Jones — because of his disdain of physical weakness — initiated a more-advanced plan of strength building with his negative-accentuated techniques and Nautilus machines. Jones proved the effectiveness of negative training, but was unable — after many attempts — to manufacture machines that emphasized it safely and productively.

Ten, twenty, and thirty years passed and there was little progression — other than cosmetic — in the function of strength-training equipment. More recently, almost all leg, torso, and arm machines from popular manufacturers contained the same characteristics. Nothing was unique.

But that's going to change in 2009.

For the last two years, in an isolated biomechanical laboratory in Sweden, exercise-machine evolution has been moving forward at a fast pace. An innovative, refined, negative-accentuated system — which, in my view, will prove to be more effective than Jones's method — is ready to emerge.

Mats Thulin of Stockholm, Sweden, is prepared to launch X-Force.

Thulin has owned and operated, over the last three decades, 127 fitness centers throughout Scandinavia. With his knowledge of club management, devotion to exercise physiology, and grasp of engineering — in conjunction with the design help of a Swedish automotive team — Thulin brings X-Force to the market.

The ingenuity of X-Force is a patented, tilting weight stack that unloads the positive phase, and then, overloads the negative. X-Force supplies negative-accentuated exercise — 40-percent extra negative resistance compared to the positive — without the use of assistants, in a series of 14 strength-training machines.

Roll over Macfadden and tell Atlas and Jones the News!

X-Force signals an end to weakness... and the beginning of a new era in strength-training equipment.

DEFINING A FEW TERMS

The performance of a strength-training machine, or a barbell, requires the raising and lowering of resistance.

When you raise the selected resistance on the weight stack, you're moving vertically against gravity and performing positive work, or in the language of physiologists, concentric muscle action is occurring.

Lowering the weight under control brings gravity into play in another fashion. The lowering portion of an exercise is called negative work or eccentric muscle action.

During positive work, your muscle fibers are shortening. During negative work the same fibers are lengthening.

In the simplest terms, observing the weight stack move during an exercise reveals: up is positive, down is negative.

(Note: In physics, positive and negative are terms that refer to the resistance or external load. While these terms are not always technically correct in their applications in this article, their interchangeable use — positive = concentric and negative = eccentric — is accepted by athletes, coaches, and fitness-minded people.)

LOOKING BACK

When I started training with weights seriously in 1959, no one paid any attention to the negative phase of an exercise. Using mostly barbells and dumbbells, we performed the positive part of each repetition with concentration. The negative phase, however, was done mindlessly. Sometimes the weight was simply dropped.

Generally, most individuals who strength trained didn't give the negative any attention. They just focused on the lifting.

My training continued in the above style until 1972. In the summer of that year, I read an article by Arthur Jones in IronMan magazine. A year earlier, Jones had established Nautilus Sports/Medical Industries in Lake Helen, Florida, and begun manufacturing a line of strength-training machines called Nautilus. In his article, Jones was irritated by the promotions of some of his competitors — competitors who manufactured friction-based machines that merely provided positive resistance. They were implying that negative resistance in a machine was a disadvantage. That prompted Jones to start experimenting with the negative phase of each repetition.

Jones was enthused by his initial gains in muscular size and strength. Toward the end of the article, he challenged bodybuilders not to think in terms of how much you can lift, but in terms of how much you can lower. That made a lasting impression on me.

Arthur Jones is shown doing negative-only pullovers on a Nautilus machine. Notice that Jones had a spotter on the side and a spotter in the back. Their job was to do the lifting or positive part of each repetition.

A 1972 STUDY

Several months later, I was in Munich, West Germany, at a scientific congress preceding the 1972 Olympics. In one of the sessions, Dr. Paavo Komi, a Finnish physiologist, described how he had trained a small group of Scandinavian weightlifters by having them lower — not lift — heavier-than-normal barbells from overhead to the floor.

His study then compared the effects of positive and negative work on the electrical activity of human muscle. He believed that his negative training of the Scandinavian lifters just might provide them with an edge in their approaching competition. Several days later, one of Dr. Komi's athletes won a gold medal and two won bronze.

I told Dr. Komi I was interested in his ongoing research and wanted to keep in touch. I also mentioned that I would soon be working with Arthur Jones at the Nautilus headquarters. Dr. Komi indicated that he'd experimented using hydraulic machines to help lift extremely heavy barbells for his athletes, but the machines had been difficult to manage.

ARTHUR JONES'S LEAP FORWARD

In September of 1972, when I returned from Europe to Florida State University to complete my post-doctorate study in nutrition, I phoned Jones and told him about Dr. Komi and his research with negative work. "Bring those reports to me immediately," Jones replied. "We don't have any time to waste."

The next day I drove to Lake Helen and gave Jones Dr. Komi's printed materials. Jones read them, shook his head several times, smiled, and led me outside, around a corner, and into a secluded factory shop where prototypes were designed. "Feast on this, Ell Darden," he said, as my eyes bulged at a sea of large, heavily constructed machines — which he named Omni.

This was the Nautilus Omni Shoulder machine in 1973. The heavier-than-normal resistance has been leg pressed to the top position, where it was then lowered with the arms slowly to the bottom. On the right side of the photo was a prototype for the Omni Supine Bench Press machine, which was never manufactured.

By the end of the day, Jones had convinced me that the lowering of heavy weights correctly was almost always ignored, yet was a central factor in achieving maximum results.

In Jones's negative training, the selected resistance on each machine was approximately 40-percent heavier than you normally handled for 10 repetitions. As a consequence, one or two people were required to do the lifting or positive phase for you. Then, it was your job to lower smoothly the resistance back to the bottom position. Your assistants lifted the weight again, and you lowered it under control.

The object of Jones's negative exercise was to lower the weight slowly, very slowly, but without interrupting the downward movement. At the start of a negative set, you should be able to stop the downward movement if you try, but do not try. After 6 or 7 repetitions, you should be unable to stop the downward movement no matter how hard you try. However, you should still be able to guide it through a smooth descent.

Finally, after 2 or 3 more repetitions you should find it impossible to stop the weight's downward acceleration. At that moment, you should terminate the set.

Properly performed negative exercise, Jones concluded, assures more complete exercise of the muscles because the resistance always moves at a smooth, steady pace and, as a result, provides more thorough stimulation of the muscle fibers. This is in contrast to a tendency to jerk and drop resistance, the manner in which a great deal of lifting was performed then and even now.

There were logistics issues, however, with Jones's negative training.

TRAINING CHALLENGES

First, is the paradoxical problem of your own strength gains. As you become stronger quickly from negative work, you must recruit two or more spotters to help with the lifting. Such serious lifting soon becomes boring for even the most motivated assistants. Furthermore, this lifting, especially on heavy leg presses and pullovers, has to be very coordinated or it can become dangerous.

Second, is the problem of continuity, maintaining the intensity of your negative work. You can easily lapse into resting too long between repetitions. A pause, or lag time, of only 3 seconds allows sufficient muscle recovery to give the illusion of improved performance, while undermining the anticipated training effect.

Furthermore, rest intervals of 3 seconds or longer between repetitions equate to performing a series of single-attempt efforts. Not only is this inefficient, it also increases the risk of injury.

THE MACHINE STALEMATE

Jones was in a quandary over designing machines with significantly more resistance on the negative stroke than on the positive stroke. He made many attempts — first, the Omni machines, which supplied a foot pedal to lift a heavier-than-normal resistance with the legs and then lower it with the arms; and last, with his servo-electrical machines that could be computer programmed to supply more resistance on the negative. Jones's endeavors provided benefits, but the machines were cumbersome and complex.

Jones sold Nautilus in 1986, and later retired from his follow-up company, MedX, in 1996. He died in 2007, without solving how-to construct an exercise machine successfully, with less positive and more negative resistance.

THE SWEDISH SOLUTION: THE MISSING KEY

On November 13, 2008, I traveled to Stockholm, Sweden, to meet with Mats Thulin, whom I had met in 1980 at a Nautilus Seminar in Florida. Mats later became a distributor of Nautilus equipment in Scandinavia. Thulin had phoned a month earlier, enthusiastic about what he called, "a new way to accentuate the negative, without the use of the legs or the help of an assistant."

In Stockholm, when I critically examined what Thulin had done — and applied it under workout conditions — a lightning bolt went off in my head... "This is the MISSING KEY. Why didn't Arthur, one of his engineers, or even me — think of this approach decades ago?"

The approach that Thulin applies so effectively involves a tilting weight stack powered by an electric motor. As the user begins the positive stroke, the weight stack leans to a 45-degree angle — instantly reducing the selected resistance by approximately 29 percent. At the apex of the positive stroke, the tilted weight stack returns to vertical. The user then lowers 100 percent of the selected resistance.

Instead of continuing to search for ways to add resistance on the negative, which was the strategy Jones and others had chosen, Thulin figured out a way to subtract weight from the positive.

This was a brilliant step forward in the evolution of eccentrics, as well as the advancement of strength-training machines.

Here's photo of an X-Force weight stack that's tilted to 45 degrees for the positive stroke of the exercise.

For example, on the X-Force Pec Seated Press machine, let's say you select 140 pounds. As you enter the machine, seat yourself properly, pull a lever, and grasp the handles, the weight stack tilts to 45 degrees. As you perform the positive phase, you are moving 100 pounds of resistance. (Note: 100 is 29-percent less than 140 pounds and 140 is 40-percent more than 100 pounds.)

Quickly, in 0.5 of a second, the weight stack goes back to the vertical position as you do a controlled negative with 140 pounds. Ideally, you would continue performing 100-pound positives and 140-pound negatives for approximately 7 or 8 full repetitions.

In addition, a properly shaped cam is incorporated on each machine to vary the resistance curve appropriately.

NO SPOTTERS, NO LAG TIME

Not only has Thulin solved the 36-year-old machine quandary, but he also has successfully overcome the two major problems with heavy negatives.

First, spotters or assistants are no longer needed, since the trainee should be able to lift the tilted — and thus reduced — resistance.

Second, what originally required a lag time — as the trainee rested while the assistants worked — is now filled by the trainee lifting the tilted resistance.

There's little chance to rest even partially when repetitions are performed correctly: positive, negative accentuated; positive, negative accentuated; and so on... as opposed to negative accentuated, rest; negative accentuated, rest; and the like.

Furthermore, X-Force's negative-accentuated training, compared to Jones's original lowering style, is safer for the muscles and connective tissues.

It will take only one, properly performed set on the X-Force Pec Seated Press machine — for instance — to feel the difference, compared to a normal set where the positive and negative resistances remain the same.

The reasons why one set on X-Force makes a meaningful difference are explained in the following sections.

THE IMPORTANCE OF INROAD

Inroad is the depletion of momentary strength, repetition by repetition, from a set of an exercise.

For example, let's say on a seated biceps-curl machine, you can do 10 repetitions with 80 pounds of resistance. (Note: This is a conventional biceps machine and you have 80 pounds on the positive and 80 pounds on the negative.) In spite of your best effort, you cannot do an 11th repetition. Why did you fail? Did your biceps strength go from something above 80 pounds down to zero?

Your strength did not go to zero. If you're a typical trainee, your repetition-by-repetition strength drops an average of 2-percent per repetition.

On repetition 1, you are 100-pounds strong — and 100 pounds of strength easily curls 80 pounds of resistance. On repetition 2, you are 98-pounds strong and 98 pounds lifts 80 pounds, and so on. On repetition 10, you are approximately 80.5 pounds strong — and 80.5 pounds of strength is barely able, with a supreme effort on your part, to curl 80 pounds on the machine. On repetition 11, you are 79 pounds strong — and 79 pounds of strength will NOT curl 80 pounds of resistance.

Continuing that example, from one set of 10 repetitions, you've made a 21-percent inroad into your starting level of strength for your biceps. According to Arthur Jones, and much Nautilus research, the most consistent level of muscular growth occurs when a trainee makes an inroad of from 15 to 25 percent on the majority of his exercise sets.

From my own strength-training history, I knew that my strength was fairly typical. In fact, my average inroad on most exercises paralleled the 2-percent, repetition-by-repetition, inroad described above. On most of my exercises, I could expect to perform approximately 10 repetitions with 80 percent of the resistance I could do one time maximally. Using a repetition style of 2 seconds on the positive and 4 seconds on the negative, then 10 repetitions required approximately 60 seconds for me to perform.

INROAD COMPARISONS

When I arrived in Stockholm, two machines, the X-Force Horizontal Leg Curl and the X-Force Biceps Curl, caught my attention. These machines, minus the tilting weight stacks, are almost identical to ones I have in my private gym in Florida. Perhaps I could make some valid inroad comparisons between X-Force and my normal weight-stack machines?

The following day, on the X-Force Horizontal Leg Curl and the X-Force Biceps Curl, I calculated and selected the same amount of resistance for the positive phases as I had used the week before in Florida. Each repetition, however, would supply 40-percent more resistance on the negative phase. My goal was to perform as many repetitions as possible, using a 2-second-positive and 4-second-negative count.

Interestingly, on both X-Force exercises, I barely completed 7 repetitions and reached momentary muscular failure at approximately 42 seconds. The week before, using my conventional leg curl and biceps curl machines, I had reached failure on each at 10 repetitions and 60 seconds.

This demonstrated to me that, with X-Force, I achieved the same inroad, 21 percent, in 42 seconds, as opposed to 60 seconds. Thus, the X-Force Horizontal Leg Curl and Biceps Curl machines, for me, were 50-percent more demanding per repetition (3-percent inroad versus 2-percent) and required 30-percent less time to failure (42 seconds versus 60 seconds).

I quickly accessed that the X-Force Horizontal Leg Curl, compared to a conventional leg curl, made a greater inroad, repetition by repetition, into my starting level of strength.

Those two factors, degree of inroad per repetition and time required to failure, showed me that X-Force, compared to conventional equipment, provides more-efficient inroads. From my 30 years of training thousands of individuals, it's been my experience that growth stimulation is closely linked to inroad and a more efficient inroad is increased assurance of growth stimulation.

X-Force's accentuate-the-negative concept has my vote for efficiency in action.

Transfers strength gains to concentric work — which is valuable in lifting performance.

Allows greater work in less time — which means more efficient training sessions and faster results.

Note: Dr. Alber's overview was assembled from discussions I had with him in Stockholm, Sweden, on November 17, 2008, and follow-up e-mails from him on December 18, 2008.

ADVANTAGES OF X-FORCE AND ITS ACCENTUATE-THE-NEGATIVE TRAINING

In comparison to conventional strength-training machines, X-Force offers these advantages by considering the following factors:

Inroad: As previously noted, because of the depth of inroad and the shorter time it takes to reach muscular failure, X-Force is more efficient.

Stimulation: A more efficient inroad equates to enhanced muscular size and strength increases.

Flexibility: To accentuate the negative allows more effective backpressure in the flexed position and more effective stretching in the extended position. Together, this contributes to full-range movement and improvements in joint flexibility.

Control: With X-Force, the trainee has solo control during both the positive lifting and the negative lowering. There's no need for spotters or assistants to help with the performance of any repetition.

Safety: The nature of accentuating the negative requires that each lowering phase be performed smoothly and slowly. And since the positive is always 29-percent less than the negative phase, the turnaround between the negative and positive transitions the user without straining into the next lowering phase. X-Force promotes better form and safety.

Rehabilitation: Because of more control, better form, and safer conditions, X-Force is a valuable means of treating and working around injuries, as well as injured body parts.

There are many ways to organize routines with X-Force machines. One way is to alternate two routines, A and B, as listed below:

A Routine

Leg Quadriceps

Leg Press

Deltoid Lift

Deltoid Press

Lat Back Circular

Biceps Curl

Triceps Press

Abdominal Crunch

B Routine

Horizontal Leg Curl

Leg Quadriceps

Pec Angle Press

Lat Back Pull

Pec Arm Cross

Pec Seated Press

Lat Back Row

Abdominal Crunch

My recommendation is to train on X-Force twice a week. For example, perform A Routine on Monday and B Routine on Thursday.

Concerning sets and repetitions, I'm a believer in one set to failure. Done properly, that's all you require for maximum stimulation. With X-Force, because of the added 40 percent on the negative, the repetition range for most trainees should be 6 to 8. Each repetition should be done with a count of 2 seconds on the positive and 4 seconds on the negative, or perhaps even slower, 3/5 or 4/6. When you can perform 8 repetitions in good form, that's the signal to add from 2- to 5-percent more resistance to that machine at the time of the next workout.

On my visit to Stockholm in November of 2008, Mats Thuline and I performed similar 8-exercise, X-Force routines — one set of 6-8 repetitions to momentary muscular failure — and each of us finished our workouts in 15 minutes.

Two 15-minute workouts a week on X-Force should be the basic frequency and duration for most fitness-minded individuals.

THE END OF WEAKNESS

Bernarr Macfadden and Charles Atlas — during the first half of the 20th Century — publicized the idea that "Weakness is a crime." This in-your-face headline worked successfully because each promoter was able to show, through his articles and mail-order courses, the confidence-building powers of... bigger, stronger muscles.

One of the many versions of the Charles Atlas ad that was so effective during the 1930s and 1940s. These promotions were always peppered with phrases such as:

"Quit being a skinny weakling.""Take charge of your life.""Build a real HE-MAN body."

Atlas, with his physical promises, provided much-needed optimism that there would be better times ahead.

Many boys and men of that era were under muscled and thin. Often, they faced long grueling days of farm work. Food was scarce. Rest was skimpy. And a world war was looming on the horizon.

Macfadden and Atlas — with their muscle-development plans — offered hope... for pennies a day.

Millions of boys and men responded. Many applied the necessary discipline and patience — and their bodies responded by becoming bigger and stronger.

Arthur Jones, with his Nautilus machines and their popularity in the 1970s, provided more hope as thousands of fitness centers opened, purchased Nautilus equipment, and sold millions of exercise memberships throughout the United States.

Today, the landscape is different. The majority of boys and men no longer spend grueling days doing anything close to strenuous work. Computers have taken the place of plows, pitchforks, and outdoor activity. Food is not only plentiful, but also loaded with taste-tested calories.

Most boys and men, at first glace, are not skinny — they're fat.

But below those fat-thickened outer shells are inner bodies that are still under muscled and weak.

Mats Thulin and his X-Force machines deliver renewed hope. Hope based on the science of eccentrics. Hope in the form of revolutionary tilting weight-stack exercises that accentuate the negative.

It only takes 30 minutes of X-Force training per week to signal:The End of Weakness.

When researchers in 1953 first used the word eccentric to describe muscle lengthening, it was spelled "ex"centric. X-Force, therefore, is a fitting name for exercise equipment that overloads the eccentric or negative movement. As a reminder, there are two heavy X-supports that stabilize the axle of the tilting weight stack on each machine.

THE BEGINNING OF A NEW ERA: "ROLL OVER BEETHOVEN"

Chuck Berry's 1956 recording, "Roll Over Beethoven," became an anthem globally accepted as symbolizing change — change that ushered in a new era called rock and roll.

X-Force, likewise, symbolizes change and a new era in strength-training equipment.

With Berry's guitar riffs in the background, here's my updated ending for his classic song...

Roll over Macfadden and tell Atlas and Jones the News:

With X-Force's line-up, you've got nothing but weakness to lose. Roll over Macfadden and dig these negative rhythm and rules.

X-Force. Negative training made simple, safe, and productive.

The Lat Back Circular, for negative-accentuated pullovers, is the centerpiece of the X-Force upper-body machines. In my opinion, Arthur Jones would have welcomed the technology and the engineering behind this quality-designed equipment.

Dr. D:
Could you please telephone Mr. Schwab and convince him to order a full line of X-Force machines?
Seriously though, may I assume that until these machines are readily available, that one may follow the A/B routine you suggested, using the same rep speeds, and applying your previously recommended Negative Accentuated guidelines to the single arm Nautilus and Medx machines?
Thanks,
Jack

Is there a website for this line of machines??? Perhaps, it was in the article and I missed it; if so, I apologize.

(Great article and I like the machines, which almost goes without saying. I once thought about an angled weight-stack sometime after I first saw Ken Hutchins use of linear-bearings, but I would have never thought of this application of tilting during exercise! Absolute genius are these machines!)

There was a line that used the same type of load angle technology back in the late 80's early 90's.

Boyer and I tried them at Gold's in Venice. I forget the name, but they were computer controlled and the weight was a solid block and not pinned increments.

If I'm not mistaken they were supposed to be part of STAIRMASTER(?) but they never got into full production.

Boyer and I thought the computer control was a little off. I think your guy has a 1/2 second transition which should be good enough. The other machines were slow in this regard, and you ended up with far too much time either waiting or not loaded correctly.

Wish I could remember the name.

I think these look great and wish the fellows good luck.

Adequately loaded eccentric actions can make a HUGE difference in the stimulus of the trainee. And it should be noted, that the load doesn't always have to be 140% on each workout.

It is quite valuable to add only 5-20% on a regular basis, and occasionally go for EM (eccentric maximums).

EM's need be used sparingly with longer recovery times (as you already know).

I posted the "teaser" website on this device in one of the Future of Exercise thread recently, but it is only a picture of it "under wraps".

Is there a website for this line of machines??? Perhaps, it was in the article and I missed it; if so, I apologize.

(Great article and I like the machines, which almost goes without saying. I once thought about an angled weight-stack sometime after I first saw Ken Hutchins use of linear-bearings, but I would have never thought of this application of tilting during exercise! Absolute genius are these machines!)

Although different in engineering, the life fitness offered greater negative resistance than positive...if you wanted it.

Other than that...It could be a while before such machines are available to all. The nice thing about the so called old days was of physical culture was that you never got the impression it would cost a lot to transform your body.

Now money seems to be a major issue. Such machines will be like apple...superior tech than Microsoft but more expensive, and therefore much less of a market share and accessibilty.

The X-Force machines are unique in that the transitions between the positive/negative and the negative/positive are gradual. On all the other adding-to-the-negative machines that I've tried, and I've experienced almost all of them, the transitions were abrupt and jerky. As a result, none of them felt smooth.

The X-Force transitions and movements are smooth, very smooth.

Best of all, you are in control. You control both the negative and the positive. You do not need spotters.

wow, i want to try these machines!they must be expensive ? why did they have to use a motor to tilt the weight stack? couldnt they simply have a lever system that would tilt the stack? when you at the finishing position of the positive rep have a lever tilt the stack upright.

the extra weight for the tilt could be off set with a more dramtic fall off in the cam? this would be alot cheaper.also, they should make doubles of these machines[preexhaust]!!

could you imagine a compound leg machine with no friction and 40% more weight on the negative? i would love to see these machines in my gym but even medx is a rare find because of price constraints.

maybe darden and his engineer friends could build a cheeper version of these machines without the motor and revamp the health club industry like the old days ! we are americans we can build a better mousetrap?

Well written, educational and informative as always. Impressive equipment to say the least but I fear the accessibility factor in this economic climate.

I had worked on a similar mechanism in the early nineties and a few other approaches to smooth transition and had them combined into a multi function home type unit. I keep going back and forth between several concepts because I am looking for form and function and efficiency/economy of design.

Those are pretty massive machines for what can be accomplished more simply. I take your word for it as to effectiveness. I will stick with my mad scientist danger routine for now to get my negative accentuated work.

The X-Force production machines do not have guide rods for the weight-stack assembly. The weight stack rests on linear bearings -- so when it tilts, there is very little friction involved.

Go back and look carefully at the photo that shows the close-up of the weight stack tilted to 45 degrees.

The size of the machines: Generally, each machine is about 20-percent larger than a similar Nautilus machine.

And yes, each X-Force machine will be more expensive than a standard Nautilus commercial machine. I don't think the exact prices have been established, but my guess is approximately 50-percent higher.

Plus, I've already seen prototypes of an X-Force home machine -- which, for example, has a tilting weight stack in the middle, surrounded by six stations, such the bench press, leg press, overhead press, lat pulldpwn, biceps curl, and abdominal crunch.

like others here, i had heard rumblings and rumors but kept it too myself and never discussed it at all.

I wondered if it would end up as talk and dreams or reality, obviously reality.

This has potential to be the biggest change in exercise since the original nautilus machines i would think.
I have some questions and comments..

Dr Darden, my question here, how would you say the cam is engineered, like a medx with a fall off in the contracted position or more like a traditional nautilus machine being more aggressive in the contracted position ???

comments:
like everyone here would love to have a local facility to get these machines [assuming they will live up to the hype of course]

However, like most here we will never see one of these machines for years at a local gym..The fitness industry in general has gotten away from quality and keeps old equipment or buys generics like strive and dynabody as they are cheeper..

To this day i have yet to see a new nautilus one machine anywhere...A guy who should know told me, that all these new machines are going to ball clubs and schools and almost none are going to fitness centers.

I would think the new eccentric machines woulod be even worse as they will be 50 percent more expensive than the nautilus one..
The eccentric machines would be more than medx and would become the most expensive machine on the market.

Of course there is one wild card here, if the new eccentric machines produced results that were OBVIOUSLY BETTER than other machines then the market might start buying them with a hope for return on there investment by advertising this advantage. The new machines must produce better results for the majority of regular people , not just athletes..

The problem here is that i have determined that the average person simply doesn't want or can't work out hard at all and the type of machine one has will not make a difference...a 30 year old man came to my home gym the other day and dispite the fact he had been at the local gym for years, i was amazed at his lack of motivation in a gym - working to failure wasn't even remotely a possabilty..

Unfortunately, the majority of people have more in common with him than they have with anyone on this board who is relatively hardcore. Do your own observations at your gyms as you see people come and go through out the years and see what you all think..

We can always buy these machines ourselves, and buying 1-2 of them may be a possabilty for me at some point -who knows, although i sure would like to be able to try them out..

Going forward, i am concerned with maintaince on these eccentric machines. If the company went out of buisness who would service them or get parts..The new technology would be harder to repair compared to other brands which anyone can fix nearly..

Would be concerned with having all this money in a machine that can only be repaired by the manufacturer and with no future guarantee of service.

CONCLUSION:
very exiting, i really want to try them out...Might look at buying a few for myself although i have some pratical concerns. It will be years-if ever- that i see any of these in my local area gyms i am afraid

Dr darden:
One more question..These new eccentric machines operate by reducing the resistance for the positve contraction and then returning the reistance to normal for the negative which equates into a heavier negative.

My quesion is, is the weight stack going to be heavy enogh for strong lifters seeing as how the positve stroke has been reduced ??
How large do the weight stackis go and how will they accomadate athletes ??
Thanks

My vote is for the X-Force cams to fall off in most of the contracted positions, similar to what MedX machines do in their single-joint exercises.

Mats Thulin has some of the best manufacturing minds in Sweden behind his X-Force system. If X-Force doesn't go well in the USA, he'll focus his machines on Scandinavia -- which he thoroughly understands. At one time, Thulin had more than 100 fitness centers in Sweden. He sold most of them three years ago, but he still has five in Stockholm.

Go back and look closely at the last photo, the X-Force Lat Back Circular. It contains a 500-pound weight stack -- which should be enough negative resistance for most of the strongest NFL players. The machines are heavy duty and built to last.

Great to say the least!
I have been waiting for more information of negatives and potential machines that will perform the task.
After over 30 years being interested in bodybuilding, I, with out a shadow of a dought, believe that negatives done corrrectly will put mass on you like no other weight lifting protocol.

The disadvantages listed WRT negative training always left me with something missing.
Dr, Darden your recomendation regarding set design and frequency are right on the money. I have just started another program of negative trainig following to the best of what my availible equiptment will provide, set design, frequency, # of sets, are producing results and fast, results meaning, heaver weights during positive test( conventional barbel sets) sets and body measurements.
The day I get to use these machines will be a day of great interest.

One thing, did you happen to measure any of your body parts to see if there were any reactions to the work outs.
I am sure that reation to a properlly conducted work out with superior tools would render immediate change or reaction by the body.
Thanks for the article

These machines look very impressive, a remarkable engineering achievment. Unfortunately in my little corner of the world (Scotland) it's hard to even track down a Nautilus machine, never mind something like this. Techno-Gym is about as good as it gets in these parts.
Feeling sorry for myself again.